Resumo. The study of the structure and dynamics of natural regeneration in the understory of plantations with exotic species, such as those of the genus Pinus , makes it possible to provide information to management, conservation and re-establishment of native species in a plant community. The aim of this study was to identify and quantify the dynamics of natural regeneration of woody tree species occurring in the understory of Pinus caribaea in Rebio of Saltinho, Pernambuco state, Brazil. Regenerating species were measured for 10 permanent plots, 1 x 50 m, and included individuals with circumference at the base to 30 cm from the ground (CAB 0, 30 m) ≤ 15 cm and height of more than one meter. The height was classified in: Class 1, shrubby tree, individuals with height 1 ≤ H ≤ 2; Class 2 with 2 height < H ≤ 3; and Class 3, with height > 3 m and ≤ 15 cm CAP. Phytosociological parameters were calculated, the dynamics of the regeneration and the Shannon index (H ‘) and evenness (J ‘) by Pielou. Protium heptaphyllum had as many individuals and value of importance (VI) and Miconia prasina the best frequency in the two surveys. How to index H ‘ of 3,32 nats. ind -1 (2007) went to 3,07 nats. ind -1 (2012), and the evenness of J ‘ of 0,85 to 0,62, and decrease for both the diversity and the distribution. The 2012 survey recorded 12,5% increase in the number of individuals, and the regenerating of 2007 had 48,31% mortality. With respect to the number of individuals and basal area, the percentage gains were greater than the losses. It is concluded that the ecological succession of understorey regeneration of the population studied, lies in positive modification, and the settlement of Pinus caribaea, is preventing the emergence of new individuals and species.